Extension cords for 120 Volt A.C. outdoor use, in order to meet Underwriter Laboratories specifications must be able to receive the blade of an inserted plug at temperatures down to -10.degree. C.
Underwriter Laboratories also requires the 20 amp receptacle openings to be at a right angle to each other and 15 amp receptacles openings to have parallel openings. Receptacles to receive both 15 amp and 20 plugs have T shaped openings.
Extension cords, particularly for outdoor use, have molded plastic receptacles. The cold hardens the plastic so that conventional female electric connectors in molded receptacles, such as made with the prior art Pfeifer, U.S. Pat. No. 3,823,392, cannot receive a blade from a male plug in cold temperatures.
Conventional 120 Volt A.C. wall receptacles are adapted to receive both 15 amp and 20 amp plug blades by having a T shaped opening. The advantage of this is that one receptacle can serve a dual purpose. There is a convenience and an economic saving of not having to provide two separate receptacles.
In the conventional wall receptacle including a T shaped opening, the female connectors are usually large stamped parts which are held, or riveted in place. The receptacles are usually hard baked plastic not in contact with the female connectors. Such receptacles are generally not subjected to great temperature differences, particularly cold temperature. They present no difficulty to male plug blades.
A prior art edge connecting female connector, such as the HEYCO.RTM. 7227 part, adapts to molding into a plastic receptacle with limited surface contact when the plastic gets hard at -10.degree. C. The HEYCO.RTM. 7227 allows a plug blade to enter. The 7227 female connector can be used in an extension cord for either a 15 amp receptacle or a 20 amp receptacle.
The 7227 female connector avoids the pressure of the cold molded plastic. When it is molded it is held open by the load bar. The folded arms of the female connector spring back into position, leaving a space in the plastic for it to flex into, once the load bar is removed. There is little surface contact between the plastic and the edges of the female connector. Thus, in the cold, the resilience of the metal and the hardness the cold plastic does not impede the entry of a plug blade.
The 7227 female connector cannot function to engage both a blade from a 15 amp plug or a blade from a 20 plug through a T opening in the receptacle.
A female connector from the conventional 120 Volt A.C. wall receptacle, which has a T shaped opening if molded into a plastic receptacle, does not adapt to allow both the 15 amp plug blade and the 20 amp plug blade to enter. At least two arms are always in full surface contact with the molded plastic of the mold and bind in the -10.degree. C. temperature.
The present invention provides a female T connector usable in a molded plastic extension cord that overcomes the above mentioned problems.
The female connector of the present invention can be progressively stamped on a linked stamping strip. The linked stamping strip enables automation in the assembly of wire sets used in the molding of extension cords with molded receptacles with T openings and the female T connector. The wire sets provide an economy in labor and material in the manufacture of the extension cords and are an enablement for further economies in labor saving and automation. The wires may be machine crimped to the female connectors.